"I was tracking along and suddenly it came close and there was a whale on my line. I was worried he was going to hit my boat so I started freaking out a little but it just came in to have a look. I was pretty excited though, it got the adrenalin pumping."
King caught the rare moment on camera.
The video shows the whale hooking on to King's line before attempting to swim away.
Despite his excitement, King was worried the whale would stay hooked to his line.
"It's bloody coming right at me. This will be interesting," he can be heard shouting.
"No no no whale! Are you serious? I've caught a whale. I've actually caught a f***ing whale. Oh no! F***. What do I do now? Whale of a tale on a 8m line."
Moments later, the whale comes free, saving King from having to break the line off.
"Yes it's just come free! Oh my god I've just won lotto. Thank you mother mature that is amazing."
It is not known what type of whale it was.
King said in all his time as a commercial fisherman he has rarely seen a whale so close to the rocks.
"I've been a commercial fisherman for years and I've only ever seen them in that close once before.
"It's just up the road from the old Whangamumu Whaling Station so it's good to see them coming back."
While catching a whale on your fishing line is rare, the Department of Conservation has asked people to be mindful of their encounters with wildlife.
Ian Angus, Manager Marine Species expert at DOC told the Herald best practice is to get your fishing gear out of the water as soon as possible.
"If you are out on the water, you need to be prepared to expect to encounter wildlife, this is NZ and we are lucky to have a lot of marine life, seabirds to whales, that need protection.
"The main message is to get your gear out of the water as soon as you can. This may help later on if the animal becomes entangled.